1. Field of the Invention
The invention relates to an optical-electric composite cable having an optical fiber(s) and plural electric wires.
2. Description of the Related Art
An optical-electric composite cable is known that is used for e.g. signal transmission between electronic devices such as personal computer or display and that an optical fiber and plural electric wires are collectively covered by a sheath. Some optical-electric composite cables are configured to prevent an increase in optical loss caused by microbending of the optical fiber (slight bending of a central axis of a core caused by pressure (lateral pressure) applied from a side surface) (See e.g. JP-A-2011-018544 and JP-A-2012-009156).
The optical-electric composite cable disclosed in JP-A-2011-018544 is constructed such that an optical fiber is arranged in the center and plural covered conductors are arranged to surround the optical fiber. In addition, high-tensile fiber such as Kevlar (trademark) is filled between the optical fiber and the plural covered conductors. In this optical-electric composite cable, an external force from outside of the sheath is absorbed by a covering of the covered conductor and is also dispersed by the high-tensile fiber, and it is thereby possible to reduce lateral pressure acting on the optical fiber.
The optical-electric composite cable disclosed in JP-A-2012-009156 is constructed such that an optical fiber is arranged so as to be in contact with an inner peripheral surface of a protective tube and plural electric wires are arranged around an outer periphery of the protective tube. In this optical-electric composite cable, since the optical fiber is protected from an external force by the protective tube, bending or twisting of the optical fiber due to the external force is suppressed and an increase in transmission loss is thus suppressed.
The related arts may be JP-A-2011-018544, JP-A-2012-009156 and Japanese patent application No. 2012-206722 (i.e., JP-B-5273284)